Property:Mithril

Mithril items are durable, weigh half as much, have their minimum STR decreased by 1, and are unbreachable if they are armor.

Durable

An item that is durable is resistant to becoming shattered and effects that would render it destroyed cause it to be shattered instead.

Unbreachable

Armor that's unbreachable gives an AC 1 higher than it would otherwise.